1. Field of the Invention
The present invention relates to a sheet processing device detachably attachable to an image forming apparatus such as printer, facsimile or copier, e.g. to a sheet processing device for feeding a sheet such as original or recording paper to an image forming apparatus or for giving a predetermined processing to a sheet discharged from the image forming apparatus.
2. Related Background Art
In recent years, the image forming apparatus such as printer or copier has advanced in speed-up and networking. Often in such an image forming apparatus, various sheet processing devices (such as devices for feeding a sheet to the main body of the image forming apparatus or devices for giving a predetermined processing to a sheet discharged from the main body of the image forming apparatus) satisfying the need for promoting user's convenience are so configured as detachably attachable. Not only do some of these sheet processing devices have a configuration that power is supplied from a power supply in the main body of the image forming apparatus, but others have the power supply in themselves. From the standpoint of saving the power consumption, some of the power-supply equipped sheet processing devices switch the power supply to ON or OFF under remote control of the main body of the image forming apparatus to save the power when the main body of the image forming apparatus does not operate.
In cases where expendable parts are exhausted to the utmost of their service life or a sheet processing device itself fails, a sheet processing device as mentioned above is required to check for operation in a single unit of processing device alone by a service man after the replacement or repair of parts.
Because of being controlled remotely from the main body of an image forming apparatus, however, the power supply mounted on a sheet processing device could not be turned ON in a detached condition from the main body of the image forming apparatus, i.e. in the condition of single separate unit. In consequence, so as to check the operation of the device there was an inconvenience that a service man had to carry a power supply capable of turning ON or OFF as a single unit to the installing position of a processor to connect with the device.
Thus, there were sheet processing devices equipped with a switch switchable to ON or OFF of a power supply as a single unit, but such a power supply had a fear that the service man might forget to return the switch to OFF after switching it to ON to check for operation in a single unit. In such cases, since the power supply of a sheet processing device that should be OFF in itself was ON, communication with the main body of the image forming apparatus may come into the isolated condition and a normal use of the processing device was disabled.
Additionally, the power source of the sheet processing device remained ON even when the main body of the image forming apparatus does not operate, thereby resulting not only in a wasteful consumption of power but also in a shorter service life of the power supply or other electric parts.